Telephone-circuit.



No. 832,746. PATENTED OCT. 9, 1906.

' M. W. PHILLIPS.

TELEPHONE CIRCUIT.

APPLICATION FILED 21120, 1906.

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UNITED STATE S PATl lNil. OFFICE.

I MILTON w. PHILLIPS, or VENTURA, CALIFORNIA.

TELEPHON E-CIRCUIT- Specification of Letters Patent.

Patented Oct. 9, 1906.

Application filed February 20,1906. Serial No. 302,086.

ment or any two instruments on the partyline is or are being used a subscriber at another instrument on the party-line cannot use his instrument or overhear the conversation which is being carried on between the two subscribers. I accomplish this object by the mechanism described herein and illustrated in the accompanying drawing, which is a diagrammatic view of one of the stations of a party-line circuit.

In the drawing, 1 is the ordinary receiverhook upon which the receiver 2 hangs when not in use. When the receiver is removed from the hook, it first engages contact 3, which is connected by line 4 with contact 5, which is located immediately below a handswitch 6 and in engagement therewith, which grounds the tip side of the line at ground 23, which ground is connected by line 24 to the receiver-hook. This switch is connected to central-energy ground 7 by line 8, armature 9 of relay 10, and line 11, which forms the winding of relay 12. As the receiver-hook moves upwardly it causes contact 3 to engage contact 13, which last contact is connected by line 14 with contact 15, which is in engagement with switch 16. Switch 16 is connected by wire 18 to armature 19 of relay 12. Normally this armature engages contact 20, which forms a terminal of line 21, which line forms the winding of relay 10 and is connected to line 22, which last line forms the sleeve side of the line. Line 22 runs from the central-energy station and is connected to retardation-coil 32, which coil is connected by line 33 to contact 25. When contact 3 engages contact 13, the sleeve side of the line is grounded, thereby causing the current to flow from battery 26 at the central-energy station to round 23, which energizes relay 10. When relay 10 is energized, armature 9 is drawn from contact 27 and caused to engage contact 28. Contact 28 is connected by line 29 to retardation-coil 30. This retardation-coil is connected by line 31 to line 11. When relay 10 is energized, it also causes armature 34 to engage contact 35, which last contact is connected to line 21. Armature 34 is connected by line 36 to retardation-coil 37, which last coil is connected by line 38 to transmitter 39.

The transmitter is connected by line 40 to line 31. Receiver 2 is connected to line 36 by line 41 and also to condenser 42 by line 43. Condenser 43 is connected by line 44 to line 38. When armature 34 engages contact 35, the line is ready for conversation. Switch 6 has extending upwardly therefrom an arm 45, which is engaged by the receiver-hook when the receiver is hung thereon. and pre.

vents switch 6 from being. operated until the receiver is off the hook. Switches 6 and 16 are connected by bar 46, so that both switches are operated together. Above switch 16 is contact 47, which is connected by line 48 to line 29. Above switch 6 is contact 49, which is connected by line 50 to line 33. Each subscribers station is equipped with like devices, similarly arranged.

Now, assuming that party No. 1 has the line for conversation with a party on another line, we will consider the action which takes place if party No. 2 removes his receiver from the hook. As the hook is raised, it grounds the tip side of the line, as before, but with a diiierent result. A portion of the current that is grounded at station No. 1 through relay 10 is picked up at station No. 2 when the receiver-hook of that station engages contact 3 thereof and returned to ground 7 of the central-energy station, thereby energizing relay 12 of station 2, which causes armature 19 of that station to disengage from contact 20 and to engage contact 25, which prevents relay 10 of that station from becoming energized, and thereby prevents the formation of the talking-circuit through that instrument. When party at station No. 1 desires to talk with another party on the same line-say party N0. 2after he takes the receiver off the hook he must cut out his local ground before he can talk with party No. 2. This is accomplished as follows: After the receiver-hook has caused the enga ement of contacts 3 and 13 he operates switc es. 6 and 16, which are connected together, to disengage said switches from contacts 5 and 15 and to engage contacts 47 and 49. The complete disengagement of said switches is not accomplished until they are in engagement with the other contacts, so as to preserve the continuity of the circuit through one or other of the relays. Party No. 2 does not operate switches 6 and 16 of his instrument, and all other parties on that line are prevented from using their instruments, as before described. Arm 45 and bar 46 are of insulating material. The retardation-coils are to be constructed with a high coefiicient of self-induction, so as to form a practical barrier to voice-currents. l/Vhen switch 6 engages contact 49 and switch 16 engages contact 47 and said switches are disengaged from contacts 5 and 15, the current flows to central-energy ground through retardation-coil 30 and connecting-lines, thereby keeping relay 10 energized and the talkingcircuit in operative condition. Should the line be busy when the subscriber at station No. 1 takes his receiver off the hook, he cannot by raising switches 6 and 16 overhear conversation on the line, as the current will flow through relay 12 and prevent the closing of his talking-circuit.

Having described my invention, what I claim as new, and desire to secure by Letters Patent, is

1. In telephone-lines provided with a plurality of substations, a talking-circuit at each substation having a relay therein provided with two armatures, said talking-circuit having retardation-coils in each side of the line; and a supplementary circuit at each substation having a relay therein provided with a single armature, said circuits, relays and armatures being so arranged and connected that the supplementary circuit at any substation renders inoperative the talking-circuit of such substation when any other talkingcircuit of an instrument on the line is being operated.

2. In telephone-lines provided with a plurality of substations, a talking-circuit at each substation having a relay therein provided with two armatures, said talking-circuit having retardation-coils in each side of the line; a transmitter, a receiver having a retardationcoil in one side and a condenser in the other side of its connections; and a supplementary cir-. cuit at each substation having a relay therein provided witha single armature, said circuits, relays and armatures being so arranged and connected that the supplementary circuit at any substation renders inoperative the talking-circuit of such station when any other talking-circuit of an instrument on the line is being operated.

3. In telephone-lines provided with a plurality of substations, a talking-circuit at each substation having a relay therein provided with two armatures retardation-coils in each side of the line a transmitter; a receiver a retardation-coil in one side and a condenser in the other side of the receiver connections; a supplementary circuit at each substation having a relay therein provided with a single armature; contacts and switches in said circuits arranged and connected as "described herein.

4. In a central-energy system having a central-energy ground and battery and a plurality of substations; a connection from the receiver-hook at each substation to a local ground; two switches lying below the receiver-hook; a rigid insulated connection between said switches; a rigid insulated bar 6X7 tending upwardly from said switches and connected thereto, said bar engaging the receiver-hook when in its inoperative position; tw'o separated contacts above said receiverhook; two contacts at each of said switches one above and one below the same, the said switches being normally in engagement with the lower of said contacts; a connection from the lower of the contacts above the receiver-hook to the lower contact of the upper switch, a connection from the upper contact above the receiver-hook to the contact below the lower switch; a connection from the upper of said switches to central-energy ground, said connection having an armature therein and in part forming the winding of a relay; a connection from the lower of said switches to the sleeve side of the line, said connection having an armature therein and in part forming the winding of a relay; two relays at each substation, one of said relays having a single armature and the other relay having two armatures a contact adjacent to the armature of the relay having but one ar mature and normally out of engagementtherewith, said contact forming a terminal of the sleeve side of the line when the station is not being used; a retardation-coil in said sleeve-line a connection between said sleeveline intermediate the terminal contact and the retardation-coil with the contact above the upper switch; a connection from the upper contact of the lower switch to centralenergy ground; a retardation-coil in said connection; a contact adjacent to one of the armatures of the relay having two armatures a connection from said contact to the line leading from the upper contact of the lower switch to central-energy ground; a contact adjacent to the armature of the relay havin two armatures; a connection from one of sai armatures to a transmitter, said connection having a retardation-coil therein, a transmitter connected to central-energy ground; a receiver connected to a condenser, a connechave hereunto subscribed my name this 13th tion between said conrdenser and the transday of February, 1906.

mitter a connection om the receiver to the connection between the transmitter and the MILTON PHILLIPS armature intermediate the armature and the Witnesses:

retardation-coil. B. T. WILLIAMS,

In witness that I claim the foregoing I DON G. BOWKER. 

